TISSUE

 Tissue is a group of similar cells that have common origin and function.

There are four principal types of tissues.

⦁ Epithelial Tissue.

⦁ Connective Tissue.

⦁ Muscle Tissue.

⦁ Nervous Tissue.

ORIGIN OF TISSUE :- 

⦁ Epithelial Tissues develop from ectoderm, endoderm and mesoderm.

⦁ Connective tissue develop from mesoderm.

⦁ Muscle tissue develop from mesoderm.

⦁ Nervous tissue develop from ectoderm.

EPITHELIAL TISSUE OR EPITHELIUM:- It is mainly 2 type

COVERING AND LINING EPITHELIUM:-  These form the outer layer of the skin and the lining of blood vessels, ducts, body cavity and interior of respiratory, digestive urinary and reproductive system.

GLANDULAR EPITHELIUM:- This forms the secreting portions of glands.

COVERING AND LINING EPITHELIUM:- 

SIMPLE EPITHELIUM:- 

⦁ Simple Epithelium consists of single layer of cells.

⦁ There are following type simple epithelium based on epithelial cell shapes.

SIMPLE SQUAMOUS EPITHELIUM:- 

⦁ This type tissue consist of a single layer of flat cells. 

⦁ Its surface resembles a floor tiles.

⦁ Location:- This epithelium lines the heart, blood vessels, lymphatic vessels, alveoli of lungs.

SIMPLE CUBOIDAL EPITHELIUM:- 

⦁ This type tissue consists of a single layer of cube shaped cells.

⦁ Location:- Kidney tubules, glands and their ducts, lining of terminal bronchioles, surface of ovaries.

SIMPLE COLUMNAR EPITHELIUM:- 

⦁ This type tissue formed by single layer of columns shape cell.

⦁ Columnar epithelium can be 2 type.

⦁ Non- ciliated simple columnar epithelium 

Location- Alimentary canal, gall bladder.

⦁ Ciliated simple columnar epithelium:- 

Location :- Uterine tube and respiratory passages.

PESUDOSTRATIFIED COLUMNAR EPITHELIUM:- 

⦁ This has only one layer of cells 

⦁ All Cell are attached to basement membrane 

⦁ However some of the cell do not reach the surface 

⦁ The Nuclei of such cell are at varying depth.

Location:- Lining of nasal cavity, sinus, auditory tube, pharynx, trachea, bronchi of lungs.

STRATIFIED EPITHELIUM:- 

⦁ This types tissue consists of several layers of cell only one of which is attach to the basement membrane.

⦁ There are following types of stratified epithelium on the base of epithelial cell shapes. 

STRATIFIED SQUAMOUSEPITHELIUM:- 

⦁ This composed of a number of layers of cells of different shapes.

⦁ The superficial layer cells are flat deepest layers cells vary in shape.

⦁ Stratified squamous epithelium can be further classified 

⦁ Non – keratinized stratified squamous epithelium:- 

⦁ The outermost layer of cells is living

⦁ Location:- conjunctiva, cornea, lining of mouth, the pharynx, esophagus, larynx, rectum, vagina, anus.

KERATINIZED STRATIFIED SQUAMOUS EPITHELIUM:- 

⦁ The surface layer consists of dead epithelial cell.

⦁ Location :- skin,hair,nails

STRATIFIED CUBOIDAL EPITHELIUM:- 

⦁ This type tissue consists of more than two layers of cube shaped cell. 

⦁ Location:- ducts of sweat gland, sebaceous gland, salivary gland, ovarian follicular cells.

STRATIFIED COLUMNAR EPITHELIUM:- 

⦁ The superficial cells are columnar in shape.

⦁ Location:- Mammary gland, larynx, portion of male urethra.

TRANSITIONAL EPITHELIUM:- 

⦁ This type tissue composed several layers of pear shape cells 

⦁ Location- Lining of urinary bladder, ureters, superior urethra 

GLANDULAR EPITHELIUM:- 

⦁ These tissue found into both endocrine and exocrine gland.

2. CONNECTIVE TISSUE:- It is most abundant and widely distributed tissue in the body 

⦁ It consists of two basic elements cells, matrix.

⦁ Cells- fibroblasts cell, adipocytes, mast cell, macrophages, plasma cell, wbc. 

⦁ Matrix consists of fibers and ground substance 

⦁ Ground substance is H2o, Hyaluronic acid, polysaccharides.

⦁ 3- types fibers founds in matrix- collagen fiber, elastic fiber, reticular fibers.

CLASIFICATION OF CONNECTIVE TISSUE:- 

LOOSE CONNECTIVE TISSUE:- It contain less fibers and more cells.

TYPES-

AREOLAR CONNECTIVE TISSUE 

Location :- Subcutaneous layer  

ADIPOSE CONNECTIVE TISSUE:- 

Consists of adipocytes which store fat

Location- Subcutaneous layer, around the hear and kidney, yellow bone marrow.

RETICULAR CONNECTIVE TISSUE:- 

Location :- Forms supporting network of liver, spleen, lymphnode.

DENSE CONNECTIVE TISSUE :- 

⦁ This type tissue contain more number of fibers so cell and fibers are compactly packed.

TYPE:- 

DENSE REGULAR CONNECTIVE TISSUE:- 

⦁ Fibers are arranged into in parallel boundless of fibers 

⦁ Location- Tendons, ligaments.

DENSE IRREGULAR CONNECTIVE TISSUE:- 

⦁ Cell and fibers are arranged disoriented.

⦁ Location:- Conective tissue into skin, capsule of kidney.

ELASTIC CONNECTIVE TISSUE:- 

⦁ Mainly contain elastic fibers 

⦁ Location- lungs, walls of elastic arteries, trachea, bronchial tube.

CARTILAGE CONNECTIVE TISSUE:- 

⦁ Mature cell of  cartilage called chondrocyte.

⦁ Immature cell of cartilage called chondroblast 

⦁ It consists of chondrocytes, collagen and elastic fiber.

TYPES:-

HYALINE CARTILAGE:- 

⦁ It is weakest and most abundant cartiuage in body 

⦁ Location – End of long bone, anterior end of ribs, part of nasal septum.

FIBRO- CARTILAGE CONNECTIVE TISSUE:- 

⦁ Strongest cartilage because it contain collagens fibers

⦁ Location:- Intervertebral disc, pubic symphasis

ELASTIC CARTILAGE CONNECTIVE TISSUE:- 

⦁ It contain elastic fibers

⦁ Location:- Auricle, Auditory tube.

⦁ BONE TISSUE:- It is two types.

⦁ COMPACT BONE TISSUE 

⦁ Location:- Outer shell of bones  

⦁ SPONGY BONE TISSUE 

⦁ Location:- outer shell of bones

LIQUID CONNECTIVE TISSUE:- 

⦁ Eg-blood

⦁ Location:- with in blood vesscles, with in chamber of heart 

(3) MUSCLE TISSUE :- 

⦁ A type of tissue composed of contractile fibers that effect movements of organ or part of the body 

⦁ Muscle tissue able to contract and relax so provide movements within body.

⦁ Based on location, structure and function it classified into 3 categories

SKELETON MUSCLE TISSUE:- 

⦁ Because it attach to skeleton system of body so called skeleton muscle 

⦁ It also called voluntary muscle because it is under our conscious control.

SMOOTH MUSCLES:- 

⦁ It is also called involuntary or visceral muscles 

⦁ These muscles found in the wall of hollow internal structure like blood vessels, wall of GIT, wall of respiratory, urogenitory tract 

CARDIAC MUSCLES:- 

⦁ It forms most of the wall of the heart 

⦁ it is involuntary muscle 

(4) NERVOUS TISSUE:- 

⦁ Nervous tissue is composed of neurons and neuroglia.

Neurons:- 

⦁ This is basic units of the nervous system.

⦁ this neurons consists 3- basic parts- cell body, axon, dendrites.

NEUROGLIA:- 

⦁ Non conducting, supportive cells of nervous system

⦁ They do not generate impules.